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Old 18th September 2006, 12:14 AM   #26
Dolf
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Join Date: Aug 2006
Posts: 26
Default RE: what fin size for a 6.8m on a S type104

Hello Del,
?It was presented as a formula for determing the "minimum required fin area" needed. Dolf, do you have a formula for determining the maximum useful fin area??
Thanks for your comment which helped me change my wording as per the post to Ian above. The rational was that 0.53 is the magic threshold for my wife and I where spin out becomes unacceptable. Hence we pick the next larger fin above the 0.53 limit. There is not such a black and white threshold for maximum size, the performance just gets progressively worse as you go larger. And for a beginner at slow speeds there is no maximum.

?And does the length of the board change either formula??
For the 99% of us less than experts: No. This is based on empirical data that I will elaborate on to my future response to Ola when I get some more time.

?And wouldn't the board width in the fin area also change the formula??
No. The maximum fin size that a board can take is related to the tail width but that is beyond my expertise and it is a different subject than the strict determination of required fin area.

Please let me know how things work for you as my formulas are always a work in progress and can use meaningful feedback to keep improving them.

Thanks,
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